1. Field of the Invention
There is an ever increasing awareness of the relationship between the health of an individual and the proper balance of a large number of compounds which are naturally produced by the body or ingested. In the physiological study of the role specific compounds play in the regulation of physiological functions, it has become essential to determine small variations in concentrations of a variety of compounds. Therefore, there is an increasing desire to find ways to enhance the sensitivity and ease with which to measure a wide variety of compounds of physiological interest.
Most assays for compounds of physiological interest employ antibodies as one of the reagents. The preparation of antibodies useful in immunoassays for haptenic compounds involves preparing a conjugate of the hapten of interest with an antigen and injecting the antigen conjugate into a xenogeneic species. With highly functionalized haptens the synthesis of the conjugate can prove a serious obstacle. Even after preparation of the conjugate, there is no assurance that the antisera produced will have the desired specificity and binding constant to be useful in an immunoassay in the concentration range of interest.
2. Description of the Prior Art
McCaman and Stetzler (1977) J. Neurochem. 28, 669, describe an enzymatic assay for detecting acetylcholine. Spector et al., J. Neurochem. 30, 685 describe a radioimmunoassay for acetylcholine. Deutsch (1976), Ph.D. Thesis, Calif. Inst. of Technology, reports that acetylcholine affects the rate of binding of .alpha.-bungarotoxin to nicotinic acetylcholine receptor.